Method of guiding medical devices

ABSTRACT

A guide system for use with an endoscope, and a method of use is disclosed. The guide system can include a track, in the form of a rail, and a mating member for engaging the rail. The guide system can also include an accessory, such as an accessory guide tube through which a medical instrument can be carried external of the endoscope. An end cap can be provided to support the track relative to the distal end of the endoscope.

CROSS REFERENCE TO RELATED PATENT APPLICATIONS

This applications cross references the following patent applicationsfiled on the same date: END 5119, “Medical Apparatus for use with anEndoscope”, and END 5121, “Encap for use with an Endoscope”.

FIELD OF THE INVENTION

The present invention relates to medical devices, and more specificallyto a medical device for use in placement of one or more medicalinstruments or accessories within a patient's body.

BACKGROUND

Minimally invasive procedures are desirable because such procedures canreduce pain and provide relatively quick recovery times as compared withconventional open medical procedures. Many minimally invasive proceduresare performed with an endoscope (including without limitationlaparoscopes). Such procedures permit a physician to position,manipulate, and view medical instruments and accessories inside thepatient through a small access opening in the patient's body.Laparoscopy is a term used to describe such an “endosurgical” approachusing an endoscope (often a rigid laparoscope). In this type ofprocedure, accessory devices are often inserted into a patient throughtrocars placed through the body wall.

Still less invasive treatments include those that are performed throughinsertion of an endoscope through a natural body orifice to a treatmentsite. Examples of this approach include, but are not limited to,cystoscopy, hysteroscopy, esophagogastroduodenoscopy, and colonoscopy.Many of these procedures employ the use of a flexible endoscope duringthe procedure. Flexible endoscopes often have a flexible, steerablesection near the distal end that can be controlled by the user byutilizing controls at the proximal end.

Some flexible endoscopes are relatively small (1 mm to 3 mm indiameter), and may have no integral accessory channel (also calledbiopsy channels or working channels). Other flexible endoscopes,including gastroscopes and colonoscopes, have integral working channelshaving a diameter of about 2.0 to 3.5 mm for the purpose of introducingand removing medical devices and other accessory devices to performdiagnosis or therapy within the patient. As a result, the accessorydevices used by a physician can be limited in size by the diameter ofthe accessory channel of the scope used. Additionally, the physician maybe limited to a single accessory device when using the standardendoscope having one working channel.

Certain specialized endoscopes are available, such as large workingchannel endoscopes having a working channel of 5 mm in diameter, whichcan be used to pass relatively large accessories, or to providecapability to suction large blood clots. Other specialized endoscopesinclude those having two working channels. One disadvantages of suchlarge diameter/multiple working channel endoscopes can be that suchdevices can be relatively expensive. Further, such largediameter/multiple working channel endoscopes can have an outer diameterthat makes the endoscope relatively stiff, or otherwise difficult tointubate.

Various references describe methods or systems that disclose externalconfigurations related to an endoscope, such as for example: U.S. Pat.No. 5,025,778, Silverstein; U.S. Pat. No. 4,947,827, Opie; US2002/107530 published Aug. 8, 2002 in the name of Sauer; U.S. Pat. No.6,352,503, Matsui. One disadvantage of known systems is the potentialfor the distal end of a device used externally of an endoscope to movein a relatively uncontrolled manner, causing the accessory to lackprecision or the ability to be maintained within a desired field of viewof the imaging capability of the endoscope.

WO 00/48506 published Aug. 24, 2000 in the name of Herrmann discloses adeformable endoscope with at least one supplementary device. The unitcomprising the endoscope and the supplementary device is said to have anon-round cross-section. Such a non-circular endoscope may bedisadvantageous from the point of view of cost, complexity, or ease incleaning/sterilization. For instance, a standard endoscope with asmooth, substantially-circular cross section can be relatively easy tosanitize and clean.

WO 00/48506 published Aug. 24, 2000 in the name of Kortenbach, disclosesmethods and devices for delivering a medical instrument over theexterior of an endoscope to allow the use of instruments too large tofit through the lumena of the endoscope. Kortenbach discloses a collarfor use with an endoscope, resilient straps, a flexible sheath having areclosable seam, flexible polymer extrusions, and a floppy tangentialsheath defining a lumen having an irregular (collapsible) cross section.Kortenbach also discloses a track with an inverted T configuration.

SUMMARY OF THE INVENTION

Applicants' have recognized the need for a medical apparatus and relatedmethods which can be used in connection with a medical device such as anendoscope to place relatively flexible and/or relatively short accessorymedical instruments within the body of a patient, without requiringexpensive modifications to the endoscope. Applicants' have alsorecognized the need for a medical apparatus and method which can be usedin connection with an endoscope to place accessory medical instrumentwithin the body of a patient, without substantially altering theflexibility of the endoscope.

In one embodiment, the present invention provides a method for using adisposable, removable guide system that allows the use of at least oneflexible accessory device with a standard endoscope. Such a method wouldprovide controlled passage of a medical accessory device, of a sizepotentially larger than what is available through the integral channel,or too flexible to push, along the length of the endoscope and into thefield of view. The method may be used with an existing endoscope whichmay have a substantially circular cross section. Additionally, themethod can have application to an endoscope that does not have anintegral working channel or to other medical devices that extend intothe body. For instance, the method may be used to position a dilator,trocar, guidewire, a clip applier, or numerous other medical devicesthat extend into the body.

In one embodiment, the present invention provides a method of advancinga medical device in a patient's body in association with a medicaldevice such as an endoscope, the method comprising the steps of:providing a flexible endoscope having an insertion length; providing acontinuous track having a length at least as long as the insertionlength of the endoscope; and associating the track with the endoscopesuch that bending of the track is substantially decoupled from bendingof the endoscope. The method can include supporting the track such thatupon flexure of the endoscope the track is able to follow a curved pathoutside the plane of bending of the endoscope. The step of supportingthe track can comprise flexibly supporting the track in spacedrelationship from the endoscope intermediate a proximal track end and adistal track end.

The present invention can also provide a method of deploying a medicaldevice within a patient's body, the method comprising the steps of:introducing a track into the patient's body; advancing a medical devicein sliding engagement distally along the track to a desired positionwithin the body; and advancing a member distally along the track todisengage the medical device from the track so as to deploy the medicaldevice within the body.

The present invention can also provide a method of removing multipletissue samples from the body of a patient comprising the steps of:associating an external track with an endoscope; disposing the endoscopeand associated track within a patient; advancing a medical devicedistally along the track; taking a first tissue sample with the aid ofthe medical device; removing the first tissue sample from the patientwhile leaving the endoscope and the track within the patient; and takinga second tissue sample with the aid of the medical device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-section view of a guide system according to oneembodiment of the present invention and showing an accessory 50 attachedto a mating member 40, with mating member 40 slidably engaging a rail30, and with rail 30 attached to a flexible attachment flange 25.

FIG. 2A is an isometric illustration of an accessory guide 50 and amating member 40 according to an embodiment of the present invention.

FIG. 2B is an isometric illustration of a rail 30, flange 25, and a thinwalled tube or sheath 27, with flange 25 attached to thin walled tube 27and flange 25 extending generally radially from thin walled tube 27.

FIG. 2C is a cross-sectional illustration showing accessory guide 50 andflange 25 supported in sliding engagement with rail 30, such thataccessory guide 50 is spaced radially from thin wall tube or sheath 27.

FIG. 3A is a front view of an end cap 55 showing several featuresincluding a gripping surface 58 and a guide notch 63.

FIG. 3B is a cross section taken at line 3-3 of FIG. 3A showinginclination angle 65.

FIG. 4A is an isometric view of the distal end of a guide system 20 inuse with an endoscope 100, and showing field of view 110.

FIG. 4B is an isometric view of the proximal end of the guide system 20in combination with an endoscope 100.

FIG. 5A-E show cross section views of various embodiments of a rail 30and a mating member 40.

FIG. 6 is a cross section view of an embodiment of the guide system 20according to the present invention showing an attachment means toconnect guide system 20 to endoscope 100 through a sheath 80 with aninverted rail 30 disposed within the sheath 80.

FIG. 7 is a side view endoscope 100 in a retroflexed curvature, showingrail 30 with a curvature radius R2 different from radius R1 of endoscope100, and also showing the rail 30 and flange 25 folding or “warping” outof the plane of curvature of the endoscope, and such that rail 30 movescircumferentially relative to endoscope 100.

FIG. 8 is a side view of rail 30 associated with an end cap 55 to directa non-articulating medical instrument 168 extending from an accessory 50(in the form of a guide tube 50) into field of view 110 at a convergencepoint 115 with an instrument 68 extending from an integral channel 93 ofendoscope 100.

FIG. 9 shows a side view of an embodiment of guide system 20 without endcap 55 being used with an articulating accessory 71 used to position thedistal end of accessory 71 into the field of view 110.

FIG. 10 is an isometric view showing one technique that may be used todirect instrument 168 from accessory 50 into field of view 110 with asnare 73 extending from integral channel 93.

FIG. 11A-C are front views of end cap 55 placed at differentorientations on endoscope 100 in order to change the relative positionof accessory 50 with respect to integral channel 93 and lens 107(andlocation of convergence point 115).

FIGS. 12A and 12B are isometric views of one method of using guidesystem 20 with accessory 50 and instrument 68 to remove a tissue 130without removing endoscope 100 from its position within the patient.

FIG. 13 shows a cross section view of a proximal end of handle 60attached to endoscope 100.

FIG. 14 is an isometric view of a distal end of endoscope 100 with rail30 wrapped around endoscope 100 in a helical arrangement.

FIG. 15 is a cross section view showing a proximal end of endoscope 100with an arrangement of a second mating member 120 being used todisengage a first device 118 from rail 30.

FIG. 16 is a side view showing a short, relatively straight andrelatively rigid device 125 supported on and slid along rail 30 along asection of endoscope 100 curved (such as by retroflexing) to have aradius R3.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is a guide system to facilitate introduction ofmedical accessories into the body of a patient. By way of example, thepresent invention is illustrated and described for application inflexible endoscopy in a colon of a human patient. However, the presentinvention is applicable for use in other medical settings, including butnot limited to, rigid endoscopy, laparoscopy, cystoscopy, hysteroscopy,esophagogastroduodenoscopy, sigmoidoscopy, proctoscopy, or enteroscopyin which the body lumens of humans or other mammals are accessed.

FIG. 1 shows a cross section of one embodiment of a guide system 20according to one embodiment of the present invention. In FIG. 1, guidesystem 20 is illustrated as generally comprising a track in the form ofguide rail 30, a mating member 40, and an accessory 50. In theembodiment shown in FIG. 1, accessory 50 can be in the form of aflexible tubular guide for receiving and guiding a medical instrumentalongside an endoscope. Guide system 20 can be used to facilitateintroduction of accessory 50 into the body of a patient by providing ameans to slide accessory 50 along the length of another medicalinstrument, such as an endoscope, in a controlled manner. Rail 30 may beflexibly supported in spaced relationship from the outer surface of theendoscope by a flexible web in the form of flange 25. Flange 25 can havea thickness t of between about 0.005 inch and about 0.030 inch, and aheight h of between about 0.020 inch and 1.0 inch. In one embodiment,height h can be between about 0.080 inch and about 0.200 inch, such asin applications related to the use of colonoscopes in colonoscopy.Flange 25 can be formed of a flexible material, such as a flexibleplastic material. One suitable material from which flange 25 can beformed is a thermoplastic elastomer, such as a material designatedcommercially as Telcar 1025-75 (available from Teknor-Apex, Pawtucket,R.I.). Height h provides standoff of accessory 50 from the outsidesurface of the endoscope. Height h can be selected to be greater than orequal to about one half the outer diameter of the endoscope with whichthe guide system 20 is used. Without being limited by theory, such aheight h may provide the advantage that upon bending/flexing of theendoscope 100, such a height h of the flange 25 can permit the rail 30to move into approximate alignment with the neutral axis of bending ofthe endoscope, so that rail 30 does not signicantly increase the bendingstiffness of the endoscope 100.

Mating member 40 is operatively coupled to rail 30 through interlockingcontours. A first contour 140 of mating member 40 can have asubstantially matching shape to a second contour 132 of rail 30, so thatmating member 40 slides along rail 30. There is a nominal clearancedistance between the mating surfaces of mating member 40 and rail 30, sothat no binding or pinching occurs when sliding one relative to theother. A nominal clearance of 0.005″ may be provided to allow sliding ofmating member 40 along rail 30 like a drawer in a drawer slide.

One or both of rail 30 and mating member 40 can be made from a flexible,low friction (“slippery”), plastic material, such as polyethylene,Teflon, or polypropylene to provide a low coefficient of frictionbetween the members as they slide relative to one another. Because thelength (as measured perpendicular to the plane of FIG. 1) of guidesystem 20 is much longer than the width (measured parallel to ahorizontal line in the plane of FIG. 1) of the cross section, variouscomponents such as rail 30, mating member 40, attachment flange 25, oraccessory 50 may be made with an extrusion process, but such a processis not required. Additionally, rail 30 and flange 25 can be formed as aunitary piece, such as by extrusion. Likewise, mating member 40 andaccessory 50 can be formed as a unitary piece, or joined by any suitableattachment method. In FIG. 1, flange 25 can include an attachment base24. Attachment base 24 can provide releasable attachment of the flange25 to the outer surface of an endoscope. For instance, attachment base24 can include an adhesive layer on a bottom surface 23, by which flange25 can be attached to an endoscope. Flange 25 may also be secured toendoscope with adhesive sprays or tapes, Velcro-like attachmentmaterials, non-adhesive silicone tape, with segments of heat shrinktubing, or other suitable attachment means. Such attachments enable rail30 to be attached to numerous sizes of standard endoscope, allowingguide system 20 to be compatible with standard equipment already ownedby a user.

FIGS. 2A-2C illustrate another embodiment of a guide system 20 of thepresent invention. FIG. 2A is an isometric view of the accessory 50 andmating member 40 of a guide system 20. FIG. 2B is an isometric view ofthe rail 30 and attachment flange 25 associated with a thin wall tube27. FIG. 2C is cross-sectional view of an assembled guide system 20,including accessory guide 50, mating member 40, rail 30, flange 25, andthin walled tube 27, which can be in the form of a flexible sheath.

In FIG. 2B and FIG. 2C, the attachment flange 25 can be attached to, orbe integrally formed with (such as by extrusion) the thin wall tube 27.Thin wall tube 27 is flexible, and can be sized to slide over anendoscope. The guide system 20 of the present invention can have ancontinuous, uninterrupted length which is substantially the same as theinsertion length (length that is meant to go inside the patient) of anendoscope 100. Alternatively, the guide system can have an overalllength that is greater than the insertion length of the endoscope 100.In one embodiment, the thin walled tube 27, the flange 25, and the rail30 can have a continuous, uninterrupted length of at least about 50centimeters, more particularly at least about 100 cm, and still moreparticularly at least about 160 cm, such as for work associated with acolonoscope and colonoscopy.

The inner diameter of the thin wall tube 27 can be sized to be slightlygreater than the outer diameter of the endoscope 100. Endoscope 100,disposed in the thin wall tube 27, can rotate relative to the tube 27,such as when endoscope 100 is retroflexed or otherwise bent or curved.Such relative rotation of the tube 27 (and so flange 25 and rail 30)with respect to the endoscope can assist in the rail 30 being capable ofmoving circumferentially relative to endoscope 100 and taking on aposition that is approximately aligned with the neutral axis of bendingof the endoscope.

The thin walled tube 27 and attachment flange 25 shown in FIGS. 2B and2C may be made from a flexible plastic, such as thermoplastic elastomer,one example of which is Telcar 1025-75 (Teknor-Apex, Pawtucket, R.I.).The wall thickness of the thin walled tube 27 and attachment flange 25may be about 0.0020″. Although connected to attachment flange 25, rail30 may be made from a different material, such as polypropylene, whichmay be used for providing ease of sliding. One suitable polypropylene isPro-fax 7823 (Basell, Wilmington, Del.). A coextrusion process may beused to form an integral extruded part from at least two differentmaterials, such as with one embodiment of rail 30 and attachment flange25.

Likewise, similar materials and processes may be used to createaccessory 50 attached to mating member 40. For embodiments whereinaccessory 50 is in the form of a flexible guide tube, accessory 50 canbe made from thermoplastic elastomer, such as Telcar 1025-75 (availablefrom Teknor-Apex of Pawtucket, R.I.). Mating member 40 can be made froma “slippery” low friction material, such as Teflon, polyethylene, orPro-fax 7823 polypropylene (available from Basell Co. of Wilmington,Del.). Mating member 40 and accessory 50 may be formed through acoextrusion process, or alternatively, may be joined together by anyother suitable joining technique.

In use, the rail 30 can be supported on the endoscope prior to insertionof the endoscope into the patient (such as by sliding the thin wall tubeor sheath 27 and rail 30 over the endoscope prior to insertion into thepatient). Once endoscope 100 is in a position within the body, matingmember 40 can be engaged with rail 30, and the mating member 40 and theaccessory 50 can then advanced along the length of the endoscope bysliding engagement with rail 30, so that accessory 50 is positioned inor near a field of view 110 (see FIG. 4A) to perform treatment ordiagnosis (such as by advancing a medical instrument through accessory50).

In the embodiments shown in FIGS. 1 and 2A-2C, the guide system 20couples rail 30 to endoscope during a procedure, but does notsubstantially stiffen the endoscope, and is removable after theprocedure without altering or disassembling endoscope. The embodimentsshown in FIG. 1 and FIGS. 2A-C permit the rail and associated accessoryguide 50 to be attached to various sizes of standard endoscopes,allowing guide system 20 to be compatible with standard endoscopesalready owned by the user, and avoiding the need to purchase additionalnew specialized capital equipment. Rail 30 can be disposable so thatafter a single patient use, it can be removed from the Endoscope anddiscarded with other medical waste. Disposability avoids therequirements for cleaning, which could be difficult and time consumingconsidering the shape of rail 30 which may incorporate a long narrowgroove. Mating member 40 and accessory 50 may also be disposable.

In the embodiments shown, the guide system 20 couples rail 30 and theassociated accessory 50 to the endoscope such that flexibility andmaneuverability of the endoscope is maintained. By way of example, butwithout limitation, the guide system of the present invention can beused with a colonoscope without appreciably changing the stiffness ofthe colonoscope and without appreciably changing the colonoscopesbending axis, due at least in part to the ability of the rail 30 to takeon a curved path different from that of the curved endoscope, and theability of rail 30 to take on a position that is approximately alignedwith the neutral axis of bending of the endoscope. Accordingly, thepresent invention obviates the need to employ a specialized endoscopehaving a non-circular cross section, or a cross section that isotherwise modified, such as to provide preferential bending or toaccommodate the use of accessories along the side of the endoscope.

Referring to FIGS. 2A-2C, guide system 20 can have a mating member 40and a rail 30 either or both of which is substantially the same lengthas, or longer than the endoscope with which they are used. Such aconfiguration allows a user to slide accessory 50 (and any instrumentsinserted through accessory 50) into a patient's body without relyingupon axial stiffness of accessory 50 (or the axial stiffness of theinstrument inserted through accessory guide 50). Without being limitedby theory, it is believed that mating member 40 and accessory guide 50can be advanced along rail 30, even though both are flexible, due atleast in part to the close clearance between rail 30 and mating member40 and the continuous, uninterrupted nature of the track provided byrail 30. The embodiments shown permit the insertion of a soft flexibleaccessory 50, a short accessory 50 that may not inherently possess therigidity to push it along the side of endoscope 100, or the insertion ofa short rigid segment.

Guide system 20 also allows for introduction of a short, rigid device125, as shown in FIG. 16. For example, a commercially available probesuch as the BRAVO™ brand pH Monitoring System available from Medtronicsof Minneapolis, Minn. has a relatively short (approx 25 mm), relativelyrigid segment. The pH monitoring system is a wireless capsule which isattached to the wall of the esophagus for approximately 48 hours, duringwhich data is transmitted to a remote (external to patient) receiver.The guide system of the present invention can be used to deploy the pHmonitoring capsule, such as by pushing the capsule through the accessory50 to the location at which the capsule is to be attached, or byattaching the capsule to the mating member 40 and pushing the capsule byadvancing mating member 40 along the length of the endoscope.Alternatively, the rail 30 can have a cross-section that is sized andshaped to permit the device to slide axially along the length of rail30, while preventing the device from disengaging from the rail.

Flexible flange 25 provides the advantage that a relatively rigiddevice, (such as for example a generally straight, relatively rigiddevice) can be pushed by sliding along rail 30, even as the flexibleendoscope is retroflexed or otherwise curved. The flexibility of theguide system 20 of the present invention decouples bending of rail 30from bending of the endoscope, so that a relatively stiff device oraccessory, that would otherwise be difficult to slide to the distal endof the endoscope, can be slid along the curved endoscope. FIG. 16illustrates schematically a relatively rigid device 125 being advancedon rail 30 around a curved segement of endoscope 100.

In another embodiment, accessory 50 can be a device having a lengthshorter than that of endoscope 100, and not form a working channel. Forexample, the accessory 50 could be in the form of a hemostatic gauzepad. The gauze pad could be attached to the distal end of the matingmember 40, such as by suture, adhesive, staples, or a clip. The gauzecould then be used to treat a bleeding site, after which the gauze padcould be pulled from the body by pulling mating member 40 backward(proximally) along the rail 30. The present invention enables one topush a member that is relatively short and/or has low axial stiffness.The guide system 20 of the present invention allows advancement of suchdevices into a patient at least in part because mating member 40 canprovide the axial support and the length needed to move such a deviceinto a patient.

Embodiments of the guide system 20 of the present invention having amating member 40 with a length that is greater than or substantiallyequal to the length of rail 30 and the insertion length of the endoscopeprovide an advantage over endoscopic systems using a engaging memberthat is not substantially the same length as a track. In such endoscopicsystems, a medical instrument to which the engaging member is attachedwill generally require sufficient axial rigidity to enable pushing ofthe medical device along the endoscope. Additionally, such endoscopicsystems can require a block or “stop” at a distal end of a surface trackso that an engaging member is not advanced off the end of the track. Incontrast, the embodiments of the guide system 20 of the presentinvention having a mating member 40 with a length greater than orsubstantially equal to that of the rail 30 and the insertion length ofthe endoscope do not require such a block feature, and provide theadvantage that accessory 50 can be advanced beyond the end of theendoscope into a field of view of the endoscope, and then retracted.

FIGS. 3A and 3B and FIGS. 4A and 4B illustrate an end cap 55 accordingto one embodiment of the present invention. FIG. 3A is an end view ofthe end cap 55, and FIG. 3B is a cross-sectional view taken alongsection line 3-3 in FIG. 3A. End cap 55 can be a component of a guidesystem 20 according to one embodiment of the present invention, oralternatively, end cap 55 can be a separate, stand alone accessory. Endcap 55 can be configured to be releasably attachable to the distal endof an endoscope 100. By releasably attachable it is meant that end cap55 can be repeatedly attached to, and removed from, the endscope withoutdamaging either the end cap 55 or endoscope. End caps 55 can be providedin various sizes to fit onto the ends of various diameter endoscopes.End cap 55 can receive the distal end of rail 30, and can help controland guide accessory 50 in a field of view 110 (see FIG. 4A) of endoscope100.

FIG. 3B shows a cross-section of the junction of the thin wall flexibletube 27, flexible attachment flange 25, and rail 30 to end cap 55. Thejunction may be accomplished by adhesive joining or any other suitablejoining method. A distal portion of the rail 30 can extend and be heldby the notch 63 so that the mating member 40 can slide along the outsidesurface of end cap 55 in a continuous, non-interrupted path.

End Cap 55 can include a relatively rigid external body, and arelatively soft internal insert 56 with a through bore 57. The insertcan include a gripping surface 58. Insert 56 and gripping surface 58 canbe provided for releasably attaching end cap 55 to endoscope 100, suchthat end cap 55 is pushed onto the distal end of endoscope 100 withoutthe need for special tools or assembly techniques to attach or removeend cap 55 to the end of the endoscope. The insert and gripping surface58 may be made from a sticky or tacky material such as silicone orneoprene, or may include adhesive to hold end cap 55 in place on thedistal end of the endoscope 100 Alternatively, end cap 55 can be held inplace using a snap fit, an interference fit, or any other suitableattachment means which permits end cap 55 to be releasably attached tothe distal end of an endoscope. The remainder of the body of end cap 55including the external body may be made from a biocompatible plastic,such as nylon 6/6, polycarbonate, or polyvinyl chloride (PVC).

End cap 55 can be provided with smooth rounded edges on its externalsurface, and connects to a distal portion of endoscope 100. The end cap55 includes a surface feature on its external surface adapted to guide amedical instrument, such as a medical instrument advanced externallyalong the endoscope (such as in an accessory guide tube 50). The surfacefeature can be in the form of a slot, such as guide notch 63. Guidenotch 63 can be shaped to receive the distal end of rail 30. The distalend of rail 30 can extend into guide notch 63 (FIG. 4A), and the distalend of rail 30 can take on a path determined by the geometry (slope orincline) of guide notch 63, so that the distal end of mating member 40sliding on rail 30 can follow a path determined by the geometry of guidenotch 63. In the embodiment shown, the guide notch 63 is inclinedradially inward from the proximal end of the guide notch to the distalend of the guide notch.

In the embodiment shown, guide notch 63 is inclined with respect to theaxis of through bore 57 (and so inclined with respect to thelongitudinal axis of the endoscope to which end cap 55 is attached). Theangle at which guide notch 63 is inclined is indicated by referencenumeral 65 to direct accessory 50 into field of view 110. This featureof end cap 55 may be useful to provide convergence of accessory 50inserted using guide system 20 to an instrument 68 inserted through anintegral channel 93 (FIG. 6) of endoscope 100. Depending on the value ofangle 65, location of a convergence point 115 (FIG. 8) may change. Inone embodiment, angle 65 may be at least about 5 degrees, and moreparticularly at least about 10 degrees. In one embodiment, the angle 65can have a value between about 10 degrees and about 30 degrees.

In an alternative embodiment to end cap 55, the flange 25 can betapered, such as by being tapered radially inwardly (e.g. with theflange height h being reduced at the distal end of the flange 25), sothat rail 30 on flange 25 is directed radially inwardly at the distalend of the guide system 20 to guide the accessory 50 both axially andradially inwardly at the distal end of the endoscope 100.

FIGS. 4A and 4B illustrate distal and proximal ends of guide system 20attached to endoscope 100. FIG. 4A shows a distal end of guide system 20with end cap 55, attachment flange 25, thin wall tubular sheath 27,mating member 40, rail 30, and endoscope 100 (extending through bore 57of end cap 55). In the embodiment shown, accessory 50 is in the form ofan external working channel 52. Working channel 52 can receive and guidea variety of medical instruments from a point outside the patient to aposition distal of the distal end of the endoscope within the patient.

As shown in FIG. 4A, the leading (distal) end of mating member 40 canhave a tapered or an inclined edge 41 shaped to allow atraumatic passagealong endoscope 100 inside a patient's body. The interface between rail30 and mating member 40 can be located to avoid pinching tissue as themating member 40 slides in rail 30, such as by locating the interfacebelow an outer surface 144 of rail 30. A smooth covering or a taperednose on the leading edge of accessory 50 can be employed.

FIG. 4B shows one embodiment of a proximal portion of guide system 20,including flexible tubular sheath 27, attachment flange 25, rail 30, anda hollow handle 60. Handle 60 includes a through bore for receiving anendoscope such that the endoscope can pass through handle 60. Handle 60may be constructed of a soft tacky material, such as neoprene orsilicone, and may include a slot 36 formed in handle 60 for receivingthe proximal end of rail 30. A funnel feature 37 at the proximal end ofslot 36 can be employed to facilitate insertion of mating member 40 intorail 30. Handle 60 may be designed to slide over the distal end of anendoscope 100, and can have an internal conical shaped surface to fitagainst a proximal portion of endoscope 100, near an introductory port105 integral to endoscope 100, as shown in FIG. 4B. Introductory port105 of endoscope 100 receives medical instruments, such as medicalinstrument 68 shown in FIG. 8. The handle 60 can be permantly fixed tothe proximal end of thin wall flexible tube/sheath 27, or alternatively,can be releasably joined to the thin wall tube/sheath 27.

FIG. 13 shows a cross section of the junction of the thin walled tube27, rail 30, and attachment flange 25 to the handle 60. The connectionof the tube 27, rail 30, and flange 25 to handle 60 can be permanent,such by use of adhesive. The subassembly comprising the handle 60, thinwalled tube 27, rail 30, flange 25, and end cap 55 can be disposable,and can releasably engage the endoscope at one or more locations. Forinstance, end cap 55 can releasably engage the endoscope 100 at a distalend of the endoscope 100, and handle 60 can releasably engage theendoscope 100 at a proximal portion of the endoscope 100, as shown inFIG. 13. In FIG. 13, handle 60 can have an inwardly facing conicalsurface that engages an outwardly facing conical surface on endoscope100.

FIG. 5A-5D show illustrative, non-limiting embodiments of crosssectional shapes of rail 30 and mating member 40 that allow slidingengagement of rail 30 and mating member 40. It will be understood thatrail 30 and mating member 40 may take on various shapes andconfigurations, such that mating member 40 interlocks with the shape ofrail 30 to allow sliding of mating member 40 along rail 30. As viewed incross section, rail 30 can have opposing arms 31 which maintainengagement of mating member 40 with rail 30. Arms 31, together with thebody of rail 30, can define a rail cavity 33 in which the mating member40 can slide. If desired, arms 31 can be provided with a desired levelof resilience, such as by material choice or dimensioning, so thatmating member 40 can be caused to disengage from rail 30 (e.g. by“unzipping” from rail 30), such as if mating member 40 is urged radiallyoutwardly from rail cavity 33. In an alternate embodiment, not shown, awire may be employed as a rail 30 to provide a path along endoscope 100.Such a wire path may be attached at a distal and proximal end ofendoscope 100, and provide a low-profile guide for accessory 50 tofollow along endoscope 100.

The embodiment shown in FIG. 5D incorporates accessory 50 (in the formof a circular working channel) within mating member 40. This embodimentcould enable the passage of accessories within a lumen of mating member40 that slides inside rail 30. For example, rail 30 may have asubstantially triangular recessed cross section that interlocks withmating member 40 having an outer contour of a triangular shape; and amedical device can slide within a lumen 42 located within mating member40. This particular embodiment may be suitable for atraumatic passage ofmating member 40 along rail 30, and when passing standard sizeaccessories with guide system 20.

In yet another embodiment, mating member 40 can be sized and shaped tofit within rail cavity 33, and not extend above rail 30. In yet anotherembodiment, as an alternative to (or variation in) the combination ofmating member 40 and accessory 50, a guide wire or guide tube having agenerally circular cross-section could be disposed in rail cavity 33 forsliding engagement with rail 30. The guide wire or guide tube could havea diameter sized, relative to the size of rail cavity 33 and rail arms31, such that the guide wire or guide tube can slide in rail cavity 33,while being maintained from disengaging from rail cavity 33 by rail arms31.

FIG. 6 illustrates an alternate embodiment of attachment flange 25 tothose shown in FIG. 1 and FIG. 2 for connecting rail 30 to endoscope100. A sheath 80 surrounds endoscope 100 and rail 30. Rail 30 can bejoined to an inner surface of sheath 80. Such an embodiment allowspassage of mating member 40 and accessory 50 within sheath 80, providingfor atraumatic passage along the tissue surface.

FIG. 7 shows a side view of rail 30 attached to endoscope 100 with oneembodiment of attachment flange 25, showing how endoscope 100 and rail30 are able to take on different curvatures, including different curvedpaths in different planes. The guide system 20 of the present inventionprovides support of the rail with respect to the endoscope 100 in amanner that decouples bending of rail 30 and flange 25 from bending ofendoscope 100. Accordingly, guide system 20 does not prevent flexing ofthe endoscope 100. Commercially available flexible endoscopes 100 havethe ability to retroflex (bend back to look upon itself) at its distalend. FIG. 7 illustrates this retroflex ability, and how rail 30 withattachment flange 25 is able to take on a path and radius of curvaturethat is different from the path and radius of curvature of theendoscope. Rail 30 can take on a radius of curvature that is some places(along the length of the endoscope 100) greater than, and in some placesless than, the corresponding radius of curvature of the endoscope 100.Without being limited by theory, it is believed that the flexibility ofthe flange 25 and rail 30 permit the flange 25 and rail 30 to deform outof the plane of curvature of the endoscope to take on a path thatreduces the elastic strain that would otherwise be present in the flange25 and rail 30. In particular, the flexible flange 25 can permit therail 30 to move into general or approximate alignment with the neutralaxis of bending of the endoscope. Accordingly, the rail 30 is not fixedin an o'clock position relative to the endoscope that requires the rail30 to be subject to tension or compression upon bending of the endoscope(as could be the case if the rail 30 where fixed at a certaincircumferential position with respect to the cross section of theendoscope). This arrangement permits the operator to retroflex theendoscope 100, and therefore allows a user to use a normal technique tomaneuver the endoscope 100 through the lumen.

By way of example, and without being limited by theory, one may considerbending of endoscope 100 with respect to bending a beam. In beambending, there is a neutral axis (generally in the center of the beamfor symmetric beam cross sections), with one beam surface being incompression, the opposite surface being in tension. A rail supported onan endoscope in such a manner that the rail is subject to tensile stressor compressive stresses upon bending of the endoscope may impede bendingof endoscope 100 because of the rail's resistance to tension and/orcompression.

The illustration in FIG. 7 shows how a flexible attachment flange 25 canminimize the affect of rail 30 on endoscope 100 bending. The height ofattachment flange 25 effectively tethers rail 30 to endoscope 100, butallows rail 30 to find a path of different curvature and/or movecircumferentially with respect to the endoscope. In compression,attachment flange 25 permits rail 30 pleat or otherwise deform (such asin a wavy fashion), minimizing the effect on endoscope 100 bending. Inembodiments including a flexible thin wall tube/sheath 27, thedecoupling of bending of the rail from bending of the endoscope can befurther enhanced due to the ability to accommodate circumferentialmovement of the tube or sheath 27 with respect to the endoscope.

FIG. 8 illustrates how end cap 55 may be used to hold a distal end ofrail 30 to endoscope 100 and present accessory 50 or instrument 168 intofield of view 110. Guide system 20 provides a convergence point 115 fora medical instrument 168 extending from an accessory 50 (in the form ofan external guide channel in FIG. 8) and an instrument 68 extending froman integral working channel 93 of endoscope 100. This feature allowsaccessory 50 and instrument 168 to be used in conjunction withinstrument 68 to perform multiple-handed therapy or diagnosis, such thatinstrument 168 and instrument 68 are not required to have separatearticulation capabilities. In contrast, an endoscope configuration thatdoes not provide the guided convergence (such as at point 115) of thepresent invention would typically require one or more instruments tohave an articulation feature or other mechanism for providing curvatureat the instrument's distal end if it is desired to have one instrumentcooperate with another in the endoscope's field of view.

Referring to FIG. 9, if the guided convergence of end cap 55 is notprovided, cooperation of multiple instruments (such as at convergencepoint 115) in field of view 110 would require one of instruments (suchas instrument 77 in FIG. 9) to have a built in articulation capability.End cap 55 with angle 65 allows a user to use standard,non-articulating, accessories or instruments to achieve new therapies ordiagnoses.

FIG. 10 shows a guidance system 20 of the present invention andillustrates a method of articulating an instrument (such as instrument168 extending from accessory 50) with a snare 73 extending from integralchannel 93 of endoscope 100. The snare 73 can be in the form of a loopedwire, and can be advanced from channel 93 to meet an instrument 168extending from accessory 50. Once the instrument 168 extends through theloop in snare 73, the curvature of instrument 168 can be increased byadvancing instrument 168 from accessory 50, and/or by retracting snare73 in channel 93. Accordingly, the instrument 168 can be positioned at adesired site (such as a tissue site on the wall of the GI tract).

FIGS. 11A-C illustrate an additional advantage of use of the end cap 55of the present invention. FIGS. 11A-C illustrate the end cap 55positioned at various o'clock positions on the distal end of endoscope100. End cap 55 can be positioned on the endoscope 100 so that accessory50 is located in a desired o'clock position with respect to one or morefeatures of the endoscope, such as integral working channel 93 oroptics/viewing lens 107. For instance, in some applications it may bedesirable to have the integral channel 93 positioned at a certaindistance with respect to accessory 50 to perform a procedure, while inother applications it may be desireable to position the viewing lens 107at a particular position relative to accessory 50 to obtain a desiredfield of view.

FIGS. 12A and 12B illustrate an alternative embodiment in which guidesystem 20 comprises an adhesive-backed elastically extensible rail, theelastically extensible rail designated by numeral 32 in FIGS. 12A and12B. Elastically extensible rail 32 can be formed of a suitableelastically extensible material, so that rail 32 elongates in tensionand folds, buckles, or otherwise bends in compression when endoscope isbent or otherwise flexed during use. Rail 32 accommodates bending of theendoscope without substantially altering the bending stiffness of theendoscope. A suitable material for rail 32 is Santoprene ThermoplasticRubber (Advanced Elastomer Systems, Akron, Ohio), and a suitableflexible adhesive for attaching rail 30 directly to the outside surfaceof the endoscope is Super 77 Spray adhesive (3M, St. Paul, Minn.). Suchan embodiment allows rail 32 to change in length or otherwise deform asendoscope 100 is bent, and may be used in embodiments where a flexibleflange 25 is not provided.

In FIGS. 12A and 12B, a tissue mass is shown being captured and severedby a snare 73 extending from a working channel of the endoscope, andgrasped by an instrument 168, such as a flexible forceps. The flexibleforceps extends through accessory 50 (which is in the form of a flexibleguide tube in FIG. 12A), and the flexible forceps can then be used towithdraw the severed tissue mass from the gastro-intestinal tractthrough the accessory 50.

FIGS. 12A and 12B show one of numerous treatment methods that may beenabled by guide system 20. Removal of multiple biopsies of a tissue130, such as large polyps currently requires removal of endoscope 100with the tissue sample 130. This can be time consuming, especially ifthe physician needs to re-introduce the endoscope 100 through a tortuouscolon. FIGS. 12A and 12B illustrates how guide system 20 would provide away to remove such an incised polyp without removing the endoscope 100.

FIG. 13 is a cross section view of a proximal end of guide system 20,including a cross section of the attachment of handle 60 to endoscope100. One component of handle 60 is a guide bar 76 that can be provided(such as by attachment to handle 60) to prevent unintentionaldisengagement of mating member 40 from rail 30. Mating member 40 can befed between the guide bar 76 and the body of handle 60 into funnelfeature 37. Guide bar 76 can prevent mating member 40 from beinginadvertently “peeled” out of or “unzipped” from rail 30 at its proximalend.

In use, a distal end of endoscope 100 can be inserted through the borein handle 60, through sheath 27, and into the bore of end cap 55.Releasable connections of handle 60 and end cap 55 to endoscope 100 maythen be made to hold guide system 20 in place during a procedure. Theinner diameter of sheath 27 is preferably sized to allow insertion ofendoscope 100 without the need for a lubricant between endoscope 100 andsheath 27. To achieve this, a nominal clearance of at least about 0.040″may be provided between the diameter of endoscope 100 and the innerdiameter of sheath 27.

The endoscope 100 with rail 30 can then inserted into the body of apatient. When desired, the physician can then introduce mating member 40into a funnel feature 37 and slide accessory 50 with mating member 40along rail 30 into the body of a patient. Accessory 50 may be a workingchannel, through which instrument 168 may be introduced. The physiciancan then extend instrument 168 into a field of view 110 to perform aprocedure.

While accessory 50 has been described primarily as an additional workingchannel, it will be understood that accessory 50 can take other forms.Other devices which can be provided as suitable accessories include, butare not limited to, a biopsy forceps, an articulating instrument, asurgical scissor, a device adapted for sewing or stapling tissue, aguidewire, a device adapted for liquid or gas injection, or a tissueablation system. For instance, various medical instruments could becould be modified to include a mating member configured to fit and slidein rail 30 (e.g. such as by permanently or non-permanently attaching amating member 40 to the instrument). Or, alternatively, the rail cavity33 and rail arms 31 can be sized and shaped to accept a particularmedical instrument for sliding engagement in rail cavity 33.

Additionally, a plurality of endoscopes 100 can be connected to eachother using guide system 20 by attaching rail 30 to one “parent”endoscope 100, and attaching mating member 40 to a second “daughter”endoscope. Such an arrangement would allow the scopes to be connectedand slide relative to each other, providing multiple perspectives of anobject within the body of a patient.

Those skilled in the art will also recognize that a plurality of rails30 may be attached to endoscope 100 to provide multiple paths forinstruments to be fed along the outside of endoscope 100. The pluralityof rails 30 may be attached to a plurality of attachment flanges 25 orto a common attachment flange 25.

FIG. 14 illustrates an embodiment of a guide system 20 wherein rail 30is wound in a generally helical fashion about an endoscope 100. Forinstance, the distal end of rail 30 can be joined to the distal end ofan endoscope 100, the rail 30 can be wound in a helical manner and in aproximal direction along the endoscopes length, with a proximal end ofthe rail 30 being joined to a proximal portion of the endoscope. In FIG.14, the distal end of rail 30 is shown associated with an end cap 55. Inone embodiment, a guide system 20 can comprise a handle 60, an end cap55, and a rail 30 extending intermediate the handle 60 and the end cap55, in which embodiment the flange 25 and flexible tube 27 may beomitted if desired. The end cap 55 can be attached to the distal end ofthe endoscope, and the rail 30 can be wound loosely about endoscope 100(or extended in a generally linear fashion along the endoscope 100 withsufficient slack in rail 30 to allow rail 30 to accommodate bending ofthe endoscope).

FIG. 15 is a cross section view showing a proximal end of a guide system20 attached to endoscope 100. One method of using guide system 20 may beto introduce a first device 118 into the body of a patient byintentionally disengaging first device 118 from rail 30 with a secondmating member 120. This can be achieved by first introducing firstdevice 118 into rail 30, then disengaging a proximal end of first device118 from rail 30 (e.g by pulling the proximal end of first device 118upward in the plane of FIG. 15 to disengage the proximal end of firstdevice 118 from the rail 30), and then introducing the second matingmember 120 into sliding engagement with the rail, so that second matingmember 120 is disposed between the first device 118 and rail 30 toeffectively “unzip” first device 118 from rail 30 as second matingmember 120 is advanced distally down the length of rail 30.

For example, first device 118 may be a guidewire, a feeding tube (e.g.to be placed in the esophageal lumen to extend from the oral cavity tothe stomach), a duct for conveying a liquid or gas, or any otherinstrument that is meant to be positioned within a body lumen fortemporary or permanent placement. The rail 30 can be positioned withinthe body lumen, such as by being associated with an endoscope which isintroduced into the body lumen. The first device can be introduced ontorail 30 and advanced distally along the rail into a predeterminedposition within the body. A proximal end of the device 118 can then bedisengaged from the rail, as shown in FIG. 15. The second mating member120 can then be introduced under guide bar 76 and into engagement withthe rail 30, and advanced axially along the rail in a distal directionto force the device 118 out of engagement with the rail 30, therebyleaving device 118 in place in the body lumen. Advancing second matingmember 120 along the rail 30, wherein member 120 is interposed betweenrail 30 and device 118, causes the device 118 to be urged out of therail 30 and deployed in a direction generally perpendicular to the rail30. As shown in FIG. 15, member 120 can have a tapered distal end toenhance the ability of member 120 to be interposed between rail 30 anddevice 118 for urging device 118 out of engagement with rail 30.

Referring again to FIG. 16, the guide system 20 of the present inventioncan provide advancement and positioning of a relatively rigid andstraight device 125 along a curved portion of an endoscope 100. In FIG.16, the device 125 can be pushed by or carried on a mating member 40.The portion of the track 30 on which device 125 is positioned can berelatively straight, in comparison with the corresponding portion of theendoscope which is curved.

While various embodiments of the present invention have been disclosed,it will be obvious to those skilled in the art that such embodiments areprovided by way of example only. The present invention may be providedin kit form with other medical devices, including medical devices usefulin the working channel of an endoscope, or with an endoscope. The kitelements can be pre-sterilized and packaged in a sealed container orenvelope to prevent contamination. The present invention may be providedas a single use disposable device, or alternatively, may be constructedfor multiple uses. Further, each element or component of the presentinvention may be alternatively described as a means for performing thefunction or functions performed by the element or component. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. Accordingly, it isintended that the invention be limited only by the spirit and scope ofthe appended claims.

1. A method of advancing a medical device in a patient's body inassociation with an endoscope, the method comprising the steps of:providing a flexible endoscope having an insertion length; providing anovertube, wherein the overtube is configured to engage the endoscope,wherein the overtube has an interior surface and an exterior surface;providing a continuous track having a length at least as long as theinsertion length of the endoscope, wherein the track is separated fromthe outer wall of the endoscope by at least one radial distance; andwherein the track is secured to the exterior surface of the overtube viaa flange; associating the track with the endoscope, wherein the act ofassociating the track with the endoscope comprises supporting the tracksuch that upon flexure of the endoscope a portion of the track in aplane of bending of the endoscope moves circumferentially with respectto the endoscope to follow a curved path outside the plane of bending ofthe endoscope; and advancing a medical device along the track.
 2. Themethod of claim 1 wherein the step of advancing the medical devicecomprises advancing a medical device by sliding the medical devicerelative to the track.
 3. The method of claim 1 wherein the step ofassociating the track with the endoscope comprises fixing the trackrelative to the endoscope at a proximal position outside the patient andat a distal position inside the patient.
 4. The method of claim 1further comprising: providing a mating member adapted for slidingengagement with the track; providing an accessory associated with themating member; and sliding the accessory from a point outside thepatient to a point inside the patient by sliding the mating memberdistally along the track.
 5. The method of claim 1, further comprisingadvancing a member along the track to separate the medical device fromthe track.
 6. A method of deploying a medical device within a patient'sbody, the method comprising the steps of: introducing a track into thepatient's body; advancing a medical device in sliding engagementdistally along the track to a desired position within the body;providing a member configured to engage the track; and disengaging themedical device from the track so as to deploy the medical device withinthe body, wherein the act of disengaging comprises advancing the memberdistally along the track, wherein the member is configured to separatethe medical device from the track in an outward direction generallyperpendicular to the track as the member is advanced distally along thetrack, wherein the act of disengaging further comprises separating atleast a portion of the medical device from the track in the outwarddirection generally perpendicular to the track; and wherein the act ofdisengaging comprises separating the medical device from the trackbeginning at a proximal portion of the medical device and ending at adistal portion of the medical device.
 7. The method of claim 6, whereinthe member is configured to peel the medical device from the track,wherein the act of disengaging further comprises peeling the medicaldevice from the track upon distal advancement of the member.
 8. Themethod of claim 6, wherein the member is configured to unzip the medicaldevice from the track, wherein the act of disengaging further comprisesunzipping the medical device from the track upon distal advancement ofthe member.